Relativistic scalar and spin-orbit density functional calculations of the electronic structure, NICS index and ELF function of the [Re2(CO)8(μ-BiPh)2] and [Re2(CO)8(μ-BiPh2)2] clusters

► Spin-orbit affects aromaticity in metallic rings. ► Phenyl groups switches off aromaticity. ► Spin-orbit affect also the electron localization function (ELF).